I think the question regarding dynamic range is valid (hopefully
@PENG will respond, he knows more than I). It's my admittedly limited understanding that these purify and hypex amps with switching supplies don't offer much in the way of dynamic headroom above rated power, unlike a standard a/b amp with unregulated supplies which can often provide an extra db or two above rated power, albeit briefly. So that may be something the prospective buyer should keep in mind. "Too much is just enough" is a rule I try to follow regarding amps; clipping is to be avoided.
Otherwise, the hypex and purify amps have SOTA performance that leaves traditional a/b amps in the dust. They really seem to approach the "straight wire with gain" ideal. Clarity? They got it.
Another point to clarify: I thought the Buckeye amps were the more budget conscious compared to the Nord and Appolon amps. I could be wrong. They are available with the latest and greatest purify modules.